| // Copyright 2018 Developers of the Rand project. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // https://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! Implementation for the Solaris family |
| //! |
| //! Read from `/dev/random`, with chunks of limited size (1040 bytes). |
| //! `/dev/random` uses the Hash_DRBG with SHA512 algorithm from NIST SP 800-90A. |
| //! `/dev/urandom` uses the FIPS 186-2 algorithm, which is considered less |
| //! secure. We choose to read from `/dev/random`. |
| //! |
| //! Since Solaris 11.3 the `getrandom` syscall is available. To make sure we can |
| //! compile on both Solaris and on OpenSolaris derivatives, that do not have the |
| //! function, we do a direct syscall instead of calling a library function. |
| //! |
| //! We have no way to differentiate between Solaris, illumos, SmartOS, etc. |
| extern crate libc; |
| |
| use rand_core::{Error, ErrorKind}; |
| use super::random_device; |
| use super::OsRngImpl; |
| |
| use std::io; |
| use std::io::Read; |
| use std::fs::{File, OpenOptions}; |
| use std::os::unix::fs::OpenOptionsExt; |
| use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering}; |
| use std::cmp; |
| |
| #[derive(Clone, Debug)] |
| pub struct OsRng { |
| method: OsRngMethod, |
| initialized: bool, |
| } |
| |
| #[derive(Clone, Debug)] |
| enum OsRngMethod { |
| GetRandom, |
| RandomDevice, |
| } |
| |
| impl OsRngImpl for OsRng { |
| fn new() -> Result<OsRng, Error> { |
| if is_getrandom_available() { |
| return Ok(OsRng { method: OsRngMethod::GetRandom, |
| initialized: false }); |
| } |
| let open = |p| OpenOptions::new() |
| .read(true) |
| .custom_flags(libc::O_NONBLOCK) |
| .open(p); |
| random_device::open("/dev/random", &open)?; |
| Ok(OsRng { method: OsRngMethod::RandomDevice, initialized: false }) |
| } |
| |
| fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { |
| match self.method { |
| OsRngMethod::GetRandom => getrandom_try_fill(dest, false), |
| OsRngMethod::RandomDevice => random_device::read(dest), |
| } |
| } |
| |
| fn test_initialized(&mut self, dest: &mut [u8], blocking: bool) |
| -> Result<usize, Error> |
| { |
| static OS_RNG_INITIALIZED: AtomicBool = ATOMIC_BOOL_INIT; |
| if !self.initialized { |
| self.initialized = OS_RNG_INITIALIZED.load(Ordering::Relaxed); |
| } |
| if self.initialized { return Ok(0); } |
| |
| let chunk_len = cmp::min(1024, dest.len()); |
| let dest = &mut dest[..chunk_len]; |
| |
| match self.method { |
| OsRngMethod::GetRandom => getrandom_try_fill(dest, blocking)?, |
| OsRngMethod::RandomDevice => { |
| if blocking { |
| info!("OsRng: testing random device /dev/random"); |
| // We already have a non-blocking handle, but now need a |
| // blocking one. Not much choice except opening it twice |
| let mut file = File::open("/dev/random") |
| .map_err(random_device::map_err)?; |
| file.read(dest).map_err(random_device::map_err)?; |
| } else { |
| self.fill_chunk(dest)?; |
| } |
| } |
| }; |
| OS_RNG_INITIALIZED.store(true, Ordering::Relaxed); |
| self.initialized = true; |
| Ok(chunk_len) |
| } |
| |
| fn max_chunk_size(&self) -> usize { |
| // The documentation says 1024 is the maximum for getrandom, but |
| // 1040 for /dev/random. |
| 1024 |
| } |
| |
| fn method_str(&self) -> &'static str { |
| match self.method { |
| OsRngMethod::GetRandom => "getrandom", |
| OsRngMethod::RandomDevice => "/dev/random", |
| } |
| } |
| } |
| |
| fn getrandom(buf: &mut [u8], blocking: bool) -> libc::c_long { |
| extern "C" { |
| fn syscall(number: libc::c_long, ...) -> libc::c_long; |
| } |
| |
| const SYS_GETRANDOM: libc::c_long = 143; |
| const GRND_NONBLOCK: libc::c_uint = 0x0001; |
| const GRND_RANDOM: libc::c_uint = 0x0002; |
| |
| unsafe { |
| syscall(SYS_GETRANDOM, buf.as_mut_ptr(), buf.len(), |
| if blocking { 0 } else { GRND_NONBLOCK } | GRND_RANDOM) |
| } |
| } |
| |
| fn getrandom_try_fill(dest: &mut [u8], blocking: bool) -> Result<(), Error> { |
| let result = getrandom(dest, blocking); |
| if result == -1 || result == 0 { |
| let err = io::Error::last_os_error(); |
| let kind = err.kind(); |
| if kind == io::ErrorKind::WouldBlock { |
| return Err(Error::with_cause( |
| ErrorKind::NotReady, |
| "getrandom not ready", |
| err, |
| )); |
| } else { |
| return Err(Error::with_cause( |
| ErrorKind::Unavailable, |
| "unexpected getrandom error", |
| err, |
| )); |
| } |
| } else if result != dest.len() as i64 { |
| return Err(Error::new(ErrorKind::Unavailable, |
| "unexpected getrandom error")); |
| } |
| Ok(()) |
| } |
| |
| fn is_getrandom_available() -> bool { |
| use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering}; |
| use std::sync::{Once, ONCE_INIT}; |
| |
| static CHECKER: Once = ONCE_INIT; |
| static AVAILABLE: AtomicBool = ATOMIC_BOOL_INIT; |
| |
| CHECKER.call_once(|| { |
| debug!("OsRng: testing getrandom"); |
| let mut buf: [u8; 0] = []; |
| let result = getrandom(&mut buf, false); |
| let available = if result == -1 { |
| let err = io::Error::last_os_error().raw_os_error(); |
| err != Some(libc::ENOSYS) |
| } else { |
| true |
| }; |
| AVAILABLE.store(available, Ordering::Relaxed); |
| info!("OsRng: using {}", if available { "getrandom" } else { "/dev/random" }); |
| }); |
| |
| AVAILABLE.load(Ordering::Relaxed) |
| } |